This invention relates to photosensitive material processing apparatus, and more particularly photosensitive material processing apparatus for use as a developing apparatus and a pre- and post-processing apparatus (e.g., bleach-fix and washing apparatus) associated therewith destined for silver salt photographic copying machines and automatic developing machines.
Silver salt photographic copying machines are of the type wherein an original image is duplicated on a photosensitive material. One of their advantages over electostatographic copying machines is that an image of higher quality can be duplicated.
In general, silver salt photographic copying machines are designed such that a photosensitive material is fed from a magazine to an exposure zone where it is exposed to an original image, and then to a processing zone where the exposed photosensitive material is developed, producing an image. The processing zone usually includes at least three serially arranged tanks, developing, bleach-fix and washing tanks through which the exposed photosensitive material is successively passed in this order, completing development.
For the purposes of effecting sensitization or desensitization and achieving optimum development for a particular type or developing characteristic of photosensitive material during the development process, it is often desirable to vary the duration of time when the photosensitive material is dipped in a developing solution in the developing tank. A prior art approach for dipping duration control is by varying the rate of transfer of the photosensitive material because the path that the material travels in the tank is of a fixed length.
This approach has a drawback because the rate of transfer of the photosensitive material must be equal throughout the processing zone. If the transfer rate is slowed down for the purpose of sensitization, for example, the photosensitive material is passed through the succeeding bleach-fix and washing tanks at the same slow speed. The entire processing time is correspondingly increased.
Then another approach which can be contemplated for dipping duration control is by varying the length of the path in the tank rather than varying the rate of transfer of the photosensitive material. This approach may be practiced in two forms. In one form, the processing zone is provided with a plurality of developing tanks having paths of different lengths, and the photosensitive material is carried into a selected tank. In the other form, there are prepared a plurality of developing tanks having paths of different lengths, and the processing zone is loaded with a selected tank. The former requires an increased space for accommodating a plurality of developing tanks. The latter requires a cumbersome and time-consuming operation for tank replacement whenever the developing conditions must be changed. Both methods are almost unfeasible for actual copying machines.